Protocols have been developed for the substantial purification of two adenovirus 2 (Ad2)-coded early polypeptides, a 21K glycoprotein and an 11K nucleoprotein. These polypeptides will be purified in quantity, and high titer monospecific antisera will be prepared. The antisera will be used in a variety of biological studies aimed to illuminate the functions, synthesis, and regulation of these polypeptides. The chemical, physical and biological properties of the purified polypeptides will also be investigated.